iPhone 13 No image, not detected by laptop

Hello guys. Iam new to repair and I really want to learn motherboard repair especially troubleshooting. I have an iPhone 13 here and I plugged charging port to an iBoot cable connected to my soldering station that has a dc power supply built into it. When injecting some voltage it draws amps before I press anything. Am I doing wrong or right and if right does this indicate a short somewhere since it’s drawing power without me prompting it to boot. The beeping is heard when it draws/ or more than 1.5 amps

Please criticise me and teach me if Iam doing anything wrong